The present invention relates to a portable or "lap-top" computer with a head mounted display which may be stereoscopic.
Conventional personal computers have included a large "QWERTY" styled keyboard, a computer housing containing the CPU, memories, accessory boards, floppy and hard disk drives, modem, etc., and a separate CRT monitor. This arrangement has a number of drawbacks. The size and weight of the various components and the numerous power and connecting cables required, plus the relatively large electrical power requirements of conventional CRT's, have tended to make the systems relatively immobile, thus confining a computer user to one place in the office or home. Furthermore, the number of large separate components have taken up considerable desk space, often rendering a desk or workstation unsuitable for any other purpose. A whole line of computer furniture has been designed around personal computers, but has not significantly reduced these problems, and, in fact, has usually resulted in creating additional space requirements. In addition, radiation from conventional CRT computer displays or VDU's has been a major concern in the workplace. Studies by the Kaiser Foundation and others have revealed that women working at computer terminals have suffered as much as double the rate of spontaneous abortions as other women. Other, long term effects from CRT radiation exposure are unknown, but are of great concern.
In response to these limitations and potential hazards of typical personal computers, portable or lap-top computers have proliferated in recent years. As the size of microprocessors and solid state memory chips have shrunk while their capabilities have expanded, the required size of the computer housings has also shrunk. As a practical matter, the size of a portable computer is no longer limited by the computer chips and memories themselves, but by the power supply, display, and the keyboard and other data I/O devices, such as disk drives and modems, etc. While power supplies, disk drives and modems, etc. have all shrunk greatly in size as well, the keyboard and display are generally the limiting factors in shrinking portable computers.
Keyboard size is limited by the requirement for keyboard switches to be easily manipulated by a user's fingers. While some lap-top computers have used stylus-actuated keyboards with correspondingly smaller switches, such keyboards tend to greatly limit the speed and accuracy with which a user can input data through the keyboard. Thus, keyboard size has shrunk to the point where further reductions in size would severely limit the input-output capabilities of a user.
Similarly, display size has been limited by the requirement for the display screen to have the capability to display a plurality of lines of readable alpha-numeric text. Heretofore, liquid crystal displays of fairly high resolution, i.e., 300-500 lines, which are sized to match the keyboard size have been used in lap-top computers. Generally, the keyboard with the computer housed therein, and the liquid crystal display, have been located in matching halves of a folding case so that the display acts as a cover for the keyboard when the computer is not in use.
While this arrangement has been proven to be generally satisfactory, the inherent limitations of liquid crystal displays have tended to limit the number of viable uses for a portable computer. For example, liquid crystal displays have limited effective viewing angles which require a viewer to be positioned almost directly in front of the display for satisfactory results. The fact that the keyboard and display have been hinged together as a single housing means that the display, of necessity, must be positioned far enough away from the user so that the keyboard can be comfortably manipulated by the user's fingers. This means that, for an average user, the display must be positioned at least 2 1/2 to 3 feet away from the user's eyes. With such a small screen, this tends to strain the eyes of any user who must spend substantial lengths of time using the computer. This is particularly true if the user happens to be myopic or has other vision problems.
The conventional folding keyboard/display arrangement presents other problems as well. The permanent attachment of the display to the keyboard means that the keyboard must always be oriented in such a fashion that the display is visible to the user. This can prevent the user from placing the keyboard in a comfortable position. A fixed display requires a viewer to fixate on one spot which greatly increases eye fatigue. Flat panel liquid crystal displays also provide no sensation of depth to the computer user. Lastly, such a fixed, flat panel display cannot be overlaid over other information or used in a "heads up" arrangement which allows the user to see both the displayed information and objects behind the display. Furthermore, if the display were not attached to the keyboard, the keyboard could then be split in half and folded over itself, thus reducing the size of the computer by half.
It is clear then, that a need exists for a portable or "lap-top" computer which uses a display which is not attached to the keyboard, which is visible in low light conditions, which does not require the computer user to fixate on a single spot, which provides the user with a depth sensation, which has low electrical power requirements, which can be readily customized for special uses, and which can be used in a heads-up fashion.